300P
Not currently visible. Last report 1308 days ago at mag 24.7. Historic peak was mag 13.8. Typical backyard telescopes will not show it. HST, JWST, or an 8–10 m class telescope might recover it with a good ephemeris.
Right ascension
—
J2000
Declination
—
J2000
Estimated magnitude
24.7
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
28
Arc unknown
Last observation
1308d ago
Fri, 17 Feb 2023 03:43:00 GMT · COBS consensus
Perihelion
2027-09-13
0.827 au
Peak window
2027-09-10 → 2027-09-17
COBS peak mag 13.8 on 2027-09-14 · perihelion 2027-09-13. Window is those dates ±3 days — not a light-curve fit.
Historic peak
13.8
COBS / analyzed peak 2027-09-14
Catalog ingest
12h ago
Venator last wrote this row 2026-09-16 13:20:17 UTC
Brightness over time (V mag)
Gold = reported observations. Steel dashed family = ensemble (nominal / outburst / fade / disruption).
Tail length
Converted to degrees from COBS (d / arcmin / arcsec). Empty until analysis has pulled the archive.
Ensemble is a first-pass H0/n photometric model plus observed samples — not a trained ML forecast yet. The background analyzer walks the catalog one object at a time so COBS is not flooded. Disruption track rises after perihelion to stand in for solar-wind stripping.
q
0.827 au
e
0.6930
i
5.67°
Ω
95.60°
ω
223.00°
a
—
MOID
—
H
—
H0 / n
—
NEO score
—
PHA score
—
RMS
—
Elongation
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COBS comet list
okComet Observation Database magnitudes and perihelion data for the full COBS list (active and inactive).
300P/Catalina
300P · 2026-09-14 18:27:56 UTC → current
Discoverer · parsed-name · 2026-09-14 18:27:56 UTC → current
CCD Observer · SRB · 3 reports · last 7755d ago
CCD Observer · TSU02 · 3 reports · last 7754d ago
Visual Observer · YOS04 · 3 reports · last 7711d ago
CCD Observer · PRY01 · 3 reports · last 4487d ago
Visual Observer · WOL01 · 2 reports · last 4491d ago
Visual Observer · GON05 · 2 reports · last 7752d ago
CCD Observer · HIL04 · 2 reports · last 4472d ago
CCD Observer · MAS01 · 2 reports · last 2839d ago
CCD Observer · NAK01 · 1 reports · last 7774d ago
Visual Observer · WYA · 1 reports · last 4494d ago
CCD Observer · PAP04 · 1 reports · last 1308d ago
CCD Observer · WAR01 · 1 reports · last 2817d ago
CCD Observer · HOR02 · 1 reports · last 7777d ago
CCD Observer · MAT08 · 1 reports · last 2883d ago
Visual Observer · MAT08 · 1 reports · last 7752d ago
CCD Observer · OHS · 1 reports · last 7712d ago
Visual Observer · TOT03 · 1 reports · last 7782d ago
Visual Observer · URB01 · 1 reports · last 7684d ago
Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.